The leukotrienes constitute a group of locally acting hormones, produced in living systems from arachidonic acid. The major leukotrienes are Leukotriene B.sub.4 (abbreviated at LTB.sub.4), LTC.sub.4, LTD.sub.4 and LTE.sub.4. The biosynthesis of these leukotrienes begins with the action of the enzyme 5-lipoxygenase on arachidonic acid to produce the epoxide known as Leukotriene A.sub.4 (LTA.sub.4), which is converted to the other leukotrienes by subsequent enzymatic steps. Further details of the biosynthesis as well as the metabolism of the leukotrienes are to be found in the book Leukotrienes and Lipoxygenases, ed. J. Rokach, Elsevier, Amsterdam (1989). The actions of the leukotrienes in living systems and their contribution to various diseases states are also discussed in the book by Rokach.
European patent applications 318,093 (May 31, 1989) and 399,818 (Nov. 28, 1990) disclose generic structures somewhat similar to the present compounds although there are no aliphatic ketones present in them. European patent applications 349,062 (Jan. 3, 1990) and 399,291 (Nov. 28, 1990, Bayer) describe quinoline-containing leukotriene biosynthesis inhibitors, which differ from the present compound most notably in that the quinoline moiety is joined to the remainder of the molecule by an ether link rather than a vinyl group. The structures of the compounds disclosed in the above patent applications are shown below. ##STR2##